Most women get a Pap smear to screen for cervical cancer. But did you know there is also a Pap test for the breast? Referred to as the Halo Breast Pap Test, from NeoMatrix, it collects “aspirate” fluid from the nipple via an auto-suction device (similar to a breast pump used by nursing women), after the breast is warmed and massaged by the machine. The cells in the fluid are then examined for abnormalities that may indicate an increased risk for developing breast cancer.
It’s called a Pap test because it comes out of the work done in the 1950s by George Papanicolaou, MD., the same doctor who pioneered the cervical Pap test. Since then, several methods for acquiring cells from nipple fluid have been developed, but the Halo test is being promoted as a fast, noninvasive procedure that doctors can incorporate into routine checkups with women as young as 25.
Breast cancer usually develops in the epithelial cells lining the milk ducts. And as with atypical cells that may be found in a tissue biopsy of the breast, atypical cells found in nipple fluid have been linked to increased risk of breast cancer—as high as four- to five-fold, researchers report. Since cell changes begin to appear long before breast cancer is detectable on imaging tests or by physical exam—up to eight years before, the company claims—the idea is that the breast Pap test can provide an extra-early warning of a woman’s risk.
To test or not to test
The practical value of the Halo test is highly debatable, however. Many women are unable to produce fluid, and only one to two percent of results are abnormal.
Moreover, it’s far from clear what you should do if atypical cells do show up, particularly if there are no suspicious findings on imaging tests (mammography, ultrasound or MRI) or palpable lumps. Much depends on whether you have other risk factors for breast cancer, such as a family history or hormone use. On the one hand, you may be more closely monitored over the years—say, with more frequent mammograms and breast exams, which can be a good thing in some cases. But you may also be referred for more aggressive, and likely unnecessary, follow-up tests.
It is also far from clear how much the test yields clues into breast cancer risk beyond other measures. A 2005 paper from the University of California, San Francisco, found that examining nipple aspirate fluid improved the ability to evaluate breast cancer risk beyond using standard risk factors alone, but that it still only modestly identified which women are at highest risk.
Other researchers have concluded that analyzing nipple fluid is of “limited diagnostic benefit” and that the test is not useful as a screening method.
More yellow lights
The presence of atypical cells does not mean you have breast cancer or will ever develop it. In fact, the cells may “correct” themselves over time. And as with other tests, there will be false negatives, where the test misses something significant, as well as false positives, where it finds things that are not associated with malignancy.
NeoMatrix boasts that Halo is approved by the Food and Drug Administration (FDA) for the collection of nipple fluid. But that means only that the test is safe, not that it’s effective. In fact, there is only one published study on it, sponsored by the manufacturer, which looked only at whether the test was practical, safe and tolerable in healthy women. It didn’t look at cancer risk, nor did it follow up to see what happened to women with atypical cells.
Bottom line: We need better breast cancer screening tests in general. Examination of nipple fluid may hold promise, but the Halo breast Pap test is not ready for prime time. Insurance companies don’t pay for it (it costs about $90, plus a lab fee), because there is inadequate evidence that it improves the diagnosis of breast cancer or reduces deaths. And it’s not a substitute for mammograms or clinical breast exams—or, if you’re at high risk, for other tests that may be warranted, such as ultrasound and/or MRI.